Field of the Invention
The field of the present application pertains to medical devices. More particularly, the field of the invention pertains to an apparatus, system, and method for performing eye surgery with a waterjet.
Description of the Related Art
A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.
The lens lies behind the iris and the pupil. It works much like a camera lens. It focuses light onto the retina at the back of the eye, where an image is recorded. The lens also adjusts the eye's focus, letting us see things clearly both up close and far away. The lens is made of mostly water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it. But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it harder to see.
Age-related cataracts can affect vision in two ways. First, clumps of protein reduce the sharpness of the image reaching the retina. The lens consists mostly of water and protein. When the protein clumps up, it clouds the lens and reduces the light that reaches the retina. The clouding may become severe enough to cause blurred vision. Most age-related cataracts develop from protein clumping. Second, the clear lens slowly changes to a yellowish/brownish color, adding a brownish tint to vision. As the clear lens slowly colors with age, it may gradually cause vision to have a brownish shade. At first, the amount of tinting may be small and may not cause a vision problem. Over time, increased tinting may make it more difficult to read and perform other routine activities.
Surgery is the only real treatment for cataracts. Each year, cataract surgeons in the United States perform over three million cataract surgeries. The vast majority of cataracts are removed using a procedure called extracapsular cataract extraction (ECCE). Extracapsular cataract extraction involves the removal of almost the entire natural lens while the elastic lens capsule (posterior capsule) is left intact to allow implantation of an intraocular lens. Less commonly this can be achieved by manual expression of the lens through a large (usually 10-12 mm) incision made in the cornea or sclera. Although it requires a larger incision and the use of stitches, this “large incision” method may be indicated for patients with very hard cataracts or other situations in which phacoemulsification is problematic.
Modern extracapsular cataract surgery is usually performed using a microsurgical technique called phacoemulsfication, whereby the cataract is emulsified with an ultrasonic handpiece and then suctioned out of the eye. Before phacoemulsification can be performed, one or more incisions are made in the eye to allow the introduction of surgical instruments. The surgeon then removes the anterior face of the capsule that contains the lens inside the eye. A phacoemulsification probe is an ultrasonic handpiece with a titanium or steel needle. The tip of the needle vibrates at ultrasonic frequency to sculpt and emulsify the cataract while a pump aspirates particles through the tip. In some techniques, a second fine steel instrument called a chopper is used from a side port to help with mechanically chopping the nucleus into smaller pieces. The cataract is usually broken into numerous pieces and each piece is emulsified and aspirated out with suction. The nucleus emulsification makes it easier to aspirate the particles. After removing all hard central lens nucleus with phacoemulsification, the softer outer lens cortex is removed with suction only. As with other cataract extraction procedures, an intraocular lens implant (IOL), is placed into the remaining lens capsule.
One possible improvement to phacoemulsification is a cataract surgery performed with lasers. Femtosecond Laser cataract surgery is rapidly emerging as a potential technology that may allow for improved precision of incision formation and emulsification of the cataract.
Although phacoemulsification and laser-based cataract surgery work well for many patients, these technologies have several shortcomings. For example, phacoemulsification ultrasound probes must propagate ultrasound energy along the length of the probe, from a proximal transducer to a distal tip. This propagation may lead to transmission of ultrasound energy along the probe to tissues in and around the eye that do not benefit from the transmission. Current lens emulsifying probes generate cavitation energy that is initiated within the area of lens nucleus and radiates outwards towards the lens capsule. This places the lens capsule at risk for damage by this energy. Ultrasound probes also tend to generate more heat than would be desirable for a procedure in the eye. Finally, it may be quite difficult to steer an ultrasound probe around corners or bends, due to the mechanical requirements of propagating the ultrasound wave along the entire instrument. In other words, the probe may have to be rigid or at least more rigid than would be desirable.
Femtosecond laser systems have been devised to assist in the removal of cataracts. These devices are used to create the entry sites through the cornea and sclera into the eye, as well as to remove the anterior face of the capsule. In addition, the femotosecond laser energy can be focused within the lens nucleus itself, and used to “pre-chop” the lens nucleus into a number of pieces that can then be more easily removed with the phacoemulsification probe. However, these lasers can only fragment the center zone of the lens that is visible within the pupil (the iris blocks the peripheral lens from laser energy), so that fracture and removal of the peripheral lens by another method is still necessary and can actually increase surgical time. They are costly to own and operate and have the additional drawback of extending operative time.
Therefore, it would be advantageous to have a method and device for treating cataracts, and potentially other eye ailments, that included many of the advantages of phacoemulsification and laser procedures without at least some of the drawbacks
Some existing solutions are discussed in several issued patents and publications. For example, U.S. Pat. No. 7,967,799 teaches a liquefaction hand-piece tip. However, the tip requires a standoff or spacer to keep the distal end from directly contacting delicate tissue. In another existing solution, United States publication 2004/0030349 creates pulses of fluid. However, the fluid needs to be heated.
Therefore, it would be beneficial to have a new method, apparatus, and system for performing surgery for various applications including eye, micro-surgery, and/or other emulsification applications.